This application claims priority to an application entitled xe2x80x9cMethod for Building a Home-Zone Database Using Measured Power Strengthxe2x80x9d filed in the Korean Industrial Property Office on Oct. 19, 1999 and there duly assigned Serial No. 99-45332.
1. Field of the Invention
The present invention relates generally to a method for building a home-zone database for a home-zone service in a mobile communication system, and in particular, to a method for building a home-zone database using the signal power strength measured via a pilot channel.
2. Description of the Related Art
In a home-zone service, a specified zone called, xe2x80x9chome zonexe2x80x9d, is associated to a mobile subscriber so that different charging rates are applied depending on whether the subscriber initiates or receives a call within the boundary of the home zone.
Assume that a mobile user has subscribed to the home-zone service, designating a zone within a specified radius centering around his/her home as the home zone. In this case, when the subscriber talks over the mobile telephone within the home zone, a charging rate equal to that of the wired telephone charge rate will be applied to the subscriber. Yet, when the subscriber talks over the mobile telephone outside of the home zone, a normal charging rate of the mobile service will be applied to the subscriber.
When a subscriber applies for the home-zone service, the service provider typically defines the home zone based on several factors, such as the position information of the base stations, the coverage limit of each base station, the install information of the base stations and topographical information of the corresponding zone, and the address information provided by the subscriber. Hence, an accurate process of defining the home zone is very important for billing purposes to both the service provider and the subscriber.
During the process of measuring the signal strength to generate a home zone list defining the home zone, occasionally, the signal strength becomes low or undetectable even though the mobile station is located very close to the base station. The reliability of the home zone list, which is collected using Pseudo Noise (PN) signal strength, depends on the multipath characteristics of the surrounding environment. Thus, in the process of generating a home zone list, a particular area that should be included in the home zone list can be excluded if the corresponding Pseudo Noise (PN) signal strength is affected by the multipath characteristics, such as a building and other structures.
Since a home zone can be defined through a binning process, a particular bin may be excluded from the sector list if the PN signal strength is unascertainable due to the above mentioned multipath characteristics.
It is, therefore, an object of the present invention to provide a method for building a home-zone database using the signal power strength measured via the pilot channel.
Another object of the invention is to estimate the pilot strength in the associated bin position where the pilot signal strength is undetectable by applying a line-fitting formula for performing interpolation on the measured pilot signals.
To achieve the above and other objects, there is provided a method for building a home-zone database using actual simulation data measured while roaming the candidate home zone service area in a mobile communication system of the type having a mobile diagnostic monitor with a GPS antenna, a mobile telephone, and a base station database. The method comprising the steps of: measuring the strength of a pilot signal received from each base station in the home-zone service area; deriving a line-fitting formula indicating a variation trend of the pilot strength of each PN (Pseudo Noise) offset according to the distance between the respective base station from the monitor device; generating a plurality of bins associated to the home-zone service area in the form of a grid; estimating the pilot strength of each bin by applying the line-fitting formula to the respective bin; and searching the base station database for the PN offsets corresponding to the pilot strengths estimated for the respective bins and reading the cell identification information for each searched PN offset to build a home-zone database.